AUTHOR=Jung Sera , Koo Kwang Min , Ryu Jaihyunk , Baek Inwoo , Kwon Soon-Jae , Kim Jin-Baek , Ahn Joon-Woo 

TITLE=Overexpression of Phosphoribosyl Pyrophosphate Synthase Enhances Resistance of Chlamydomonas to Ionizing Radiation

JOURNAL=Frontiers in Plant Science

VOLUME=12

YEAR=2021

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2021.719846

DOI=10.3389/fpls.2021.719846

ISSN=1664-462X

ABSTRACT=<p>The enzyme phosphoribosyl pyrophosphate synthase (PRPS) catalyzes the conversion of ribose 5-phosphate into phosphoribosyl diphosphate; the latter is a precursor of purine and pyrimidine nucleotides. Here, we investigated the function of PRPS from the single-celled green alga <italic>Chlamydomonas reinhardtii</italic> in its response to DNA damage from gamma radiation or the alkylating agent LiCl. <italic>CrPRPS</italic> transcripts were upregulated in cells treated with these agents. We generated <italic>CrPRPS</italic>-overexpressing transgenic lines to study the function of CrPRPS. When grown in culture with LiCl or exposed to gamma radiation, the transgenic cells grew faster and had a greater survival rate than wild-type cells. <italic>CrPRPS</italic> overexpression enhanced expression of genes associated with DNA damage response, namely <italic>RAD51</italic>, <italic>RAD1</italic>, and <italic>LIG1.</italic> We observed, from transcriptome analysis, upregulation of genes that code for key enzymes in purine metabolism, namely <italic>ribonucleoside-diphosphate pyrophosphokinase subunit M1</italic>, <italic>adenylate kinase</italic>, and <italic>nucleoside-diphosphate kinase</italic>. We conclude that <italic>CrPRPS</italic> may affect DNA repair process via regulation of <italic>de novo</italic> nucleotide synthesis.</p>